I maintain a small website and found Markdown was perfect for easily adding content. I use the most popular formatting (bold, italic, lists, links, images) plus an occasional horizontal rule.
I bought and, very quickly, gave up on Ulysses because it doesn’t use standard forms of Markdown but rather its own proprietary version. You have to learn a non-standard Markdown syntax in this app. What’s more, most of the texts I’ve written in Markdown via Drafts, or similar, do not show properly in Ulysses so it is basically useless. I spent more time trying to wrangle text I’d written in Ulysses into standard html format on output than if I’d written it as html directly!!
My advice would be, if you want to explore Markdown, stick with Drafts or another plain text editor that can offer you a preview (Byword is a good one).